The story of Demon’s Crystals (related in half-assed text scrolls at the very beginning and end) is some evil monsters arrived and changed everyone into monsters, strange since you control half-dragon half human characters, but whatever, kill them all and reclaim your crystals back using magical guns, because it’s a twin stick shooter.
The hordes making up a stage will require you to collect a set number of crystals, kill a set number of enemies, or do both under the time limit, but besides that, it’s very typical of the genre. You get a good array of power ups with time limited usage, a very simple level up system (which makes you take and dish more damage) but there’s not loadout or any sort of customization or depth,
It would be a decent game of this genre, more on the “budget” side (not helped by the “halloween store” aesthetic), simple but fun, with a decent difficulty curve. Shame that the camera is a weird – and bad – compromise between isometric and “bird’s eye”, and in heated moments it becomes hard to tell which are your bullet or the enemy’s (when they don’t get accidentally camouflaged by the level), if you manage to see them coming at all, who knows what specific part of the stage will bother to block them.
This is especially noticeable during the few boss fights, especially the final one, which – on top of being cheap and frustrating – may obscure half the screen, when its routines don’t bug or glitch out.
When the game doesn’t randomly crash at the continue screen, which it loves to do – a LOT – at the final boss. Lovely.
You have local co-op, some competitive online modes and a survival mode, but… yeah, play Ruiner or anything by Housemarque, instead.